I think it's the cost. You can make a cheap driver off 120V that looks like shit and has terrible thermals.
A solid driver with good filtering and good thermal characteristics is expensive. So you're left with a $15 LED bulb that sits on a shelf next to $5 bulbs, selling to customers who see nothing other than two LED bulbs where one is grossly overpriced for no reason they can comprehend
As a software developer, the fact that I even have to build custom electrical hardware is a significant barrier.
The fact that this hardware runs at 120v (or 240v in my case) makes it the barrier higher as there's now a chance that making mistakes might kill me.
Additionally, the high power levels mean that adequate cooling is needed, and as a non-expert it's hard for me to know whether I've done that correctly.
A solid driver with good filtering and good thermal characteristics is expensive. So you're left with a $15 LED bulb that sits on a shelf next to $5 bulbs, selling to customers who see nothing other than two LED bulbs where one is grossly overpriced for no reason they can comprehend